Mathematics – Commutative Algebra
Scientific paper
2007-04-16
Mathematics
Commutative Algebra
26 pages
Scientific paper
Let $\mathfrak a$ denote an ideal of a local ring $(R, \mathfrak m).$ Let $M$ be a finitely generated $R$-module. There is a systematic study of the formal cohomology modules $\varprojlim \HH^i(M/\mathfrak a^nM), i \in \mathbb Z.$ We analyze their $R$-module structure, the upper and lower vanishing and non-vanishing in terms of intrinsic data of $M,$ and its functorial behavior. These cohomology modules occur in relation to the formal completion of the punctured spectrum $\Spec R \setminus V(\mathfrak m).$ As a new cohomological data there is a description on the formal grade $\fgrade(\mathfrak a, M)$ defined as the minimal non-vanishing of the formal cohomology modules. There are various exact sequences concerning the formal cohomology modules. Among them a Mayer-Vietoris sequence for two ideals. It applies to new connectedness results. There are also relations to local cohomological dimensions.
No associations
LandOfFree
On the formal cohomology of local rings does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the formal cohomology of local rings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the formal cohomology of local rings will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-44564